Spectroscopic variabilities in lambda Pavonis

Spectroscopic variabilities in lambda Pavonis

Author Levenhagen, Ronaldo Savarino Autor UNIFESP Google Scholar
Leister, N. V. Google Scholar
Kuenzel, R. Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Universidade de São Paulo (USP)
Abstract Aims. We investigate the time-varying patterns in line profiles, V/R, and radial velocity of the Be star HD 173948 (lambda Pavonis).Methods. Time series analyses of radial velocity, V/R, and line profiles of He I, Fe II, and Si II were performed with the Cleanest algorithm. An estimate of the stellar rotation frequency was derived from the stellar mass and radius in the Roche limit by adopting an aspect angle i derived from the fittings of non-LTE model spectra affected by rotation. the projected rotation velocity, necessary as input for the spectral synthesis procedure, was evaluated from the Fourier transform of the rotation profiles of all neutral helium lines in the optical range.Results. Emission episodes in Balmer and He i lines, as well as V/R cyclic variations, are reported for spectra observed in year 1999, followed by a relatively quiescent phase (2000) and then again a new active epoch (2001). From time series analyses of line profiles, radial velocities, and V/R ratios, four signals with high confidence levels are detected: nu(1) = 0.17 +/- 0.02, nu(2) = 0.49 +/- 0.05, nu(3) = 0.82 +/- 0.03, and nu(4) = 1.63 +/- 0.04 c/d. We interpret nu 4 as a non-radial pulsation g-mode, nu 3 as a signal related to the orbital timescale of ejected material, which is near the theoretical rotation frequency 0.81 c/d inferred from the fitting of the models taken into account for gravity darkening. the signals nu(1) and nu(2) are viewed as aliases of nu(3) and nu(4).
Keywords stars: oscillations
stars: fundamental parameters
stars: emission-line, Be
stars: individual: lambda Pavonis
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Grant number FAPESP: 04/14256-8
FAPESP: 2010/06814-4
CNPq: 307095/2008-8
CNPq: 1998/10138-8
Date 2011-09-01
Published in Astronomy & Astrophysics. Les Ulis Cedex A: Edp Sciences S A, v. 533, 8 p., 2011.
ISSN 0004-6361 (Sherpa/Romeo, impact factor)
Publisher Edp Sciences S A
Extent 8
Origin http://dx.doi.org/10.1051/0004-6361/201116590
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000295168100075
URI http://repositorio.unifesp.br/handle/11600/33976

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